Expandable-mouth catheter delivery-assist tool

Abstract

In some examples, a medical assembly includes a catheter and a delivery-assist tool. The catheter includes an elongated body comprising a proximal body portion and a distal body portion and defining a body inner lumen; and an expandable member located at the distal body portion, the expandable member defining an expandable member inner lumen. The delivery-assist tool includes a support structure configured to extend through the body inner lumen and the expandable member inner lumen of the catheter; and a flexible cover coupled to a distal portion of the support structure, wherein the flexible cover is configured to facilitate compression and retention of the expandable member in a delivery configuration while being advanced through a delivery sheath and while the support structure extends through the body inner lumen and the expandable member inner lumen.

What is claimed is: 
     
       1. A medical assembly comprising:
 a catheter comprising:
 an elongated body comprising a proximal body portion and a distal body portion and defining a body inner lumen, wherein the proximal body portion defines a proximal opening to the body inner lumen and the distal body portion defines a distal opening to the body inner lumen; and 
 an expandable member located at the distal body portion, the expandable member defining an expandable member inner lumen, wherein the expandable member is configured to expand radially outward from a delivery configuration to a deployed configuration, and wherein the expandable member inner lumen is in fluid communication with the body inner lumen; and 
 
 a delivery-assist tool comprising:
 a support structure configured to extend through the body inner lumen and the expandable member inner lumen; and 
 a flexible cover coupled to a distal portion of the support structure, wherein the flexible cover is configured to facilitate compression and retention of the expandable member in the delivery configuration while the catheter is being advanced through a delivery sheath and while the support structure extends through the body inner lumen and the expandable member inner lumen, and wherein the flexible cover is configured to invert and proximally withdraw through the body inner lumen in response to a proximal force applied to the support structure. 
 
 
     
     
       2. The assembly of  claim 1 , wherein the flexible cover has a funnel shape defining a proximal-facing mouth when the flexible cover is disposed over the expandable member and is compressing the expandable member. 
     
     
       3. The assembly of  claim 1 , wherein the flexible cover is configured to extend distally past a distal-most end of the expandable member, and further configured to apply an axial tensile force to the expandable member while the flexible cover is disposed over the expandable member and while the flexible cover and the expandable member are disposed within the delivery sheath. 
     
     
       4. The assembly of  claim 1 , wherein the flexible cover comprises a braided mesh. 
     
     
       5. The assembly of  claim 4 , wherein the braided mesh comprises Nitinol. 
     
     
       6. The assembly of  claim 4 , wherein the braided mesh comprises polyethylene terephthalate (PET). 
     
     
       7. The assembly of  claim 4 , wherein the braided mesh defines a first braid angle that is greater than a second braid angle of the expandable member. 
     
     
       8. The assembly of  claim 1 , wherein the flexible cover comprises a plurality of polymer flaps extending proximally and radially outward from the support structure. 
     
     
       9. The assembly of  claim 1 , wherein the flexible cover comprises a plurality of Nitinol petals extending proximally and radially outward from the support structure. 
     
     
       10. The assembly of  claim 1 , wherein the flexible cover comprises a coil structure extending helically around the support structure. 
     
     
       11. The assembly of  claim 1 , wherein the support structure comprises polymer. 
     
     
       12. The assembly of  claim 1 , wherein the support structure defines a varying hardness along an axial length of the support structure. 
     
     
       13. The assembly of  claim 12 , wherein the support structure defines a proximal portion and the distal portion, wherein the distal portion defines a hardness that is less than a hardness of the proximal portion. 
     
     
       14. The assembly of  claim 1 , further comprising the delivery sheath. 
     
     
       15. The assembly of  claim 1 , wherein the catheter further comprises a locking mechanism configured to engage with the support structure of the delivery-assist tool to minimize or prevent longitudinal movement of the delivery-assist tool relative to the catheter. 
     
     
       16. The assembly of  claim 15 , wherein the locking mechanism comprises a hemostasis valve. 
     
     
       17. A catheter comprising:
 an elongated body including a proximal body portion and a distal body portion and defining a body inner lumen, wherein the proximal body portion defines a proximal opening to the body inner lumen and the distal body portion defines a distal opening to the body inner lumen; 
 an expandable member located at the distal body portion, the expandable member forming an expandable member inner lumen, the expandable member inner lumen defining a distal extension of the body inner lumen in fluid communication with the body inner lumen, wherein the expandable member is configured to expand radially outward from a delivery configuration to a deployed configuration; and 
 a delivery-assist tool configured to be received within the body inner lumen and the expandable member inner lumen, the delivery-assist tool comprising a support structure and a mesh cover configured to apply an axial tensile force to the expandable member to facilitate compression of the expandable member into the delivery configuration as the expandable member and the mesh cover are advanced through a delivery sheath, wherein the mesh cover is configured to invert and proximally withdraw through the body inner lumen in response to a proximal force applied to the support structure. 
 
     
     
       18. The catheter of  claim 17 , wherein the mesh cover defines a first braid angle that is greater than a second braid angle of the expandable member. 
     
     
       19. A method comprising:
 introducing a delivery-assist tool comprising a support structure and a flexible cover coupled to a distal portion of the support structure into a body inner lumen of a catheter, wherein the elongated body comprises a proximal body portion and a distal body portion, wherein the proximal body portion defines a proximal opening to the body inner lumen and the distal body portion defines a distal opening to the body inner lumen, wherein introducing the delivery-assist tool comprises advancing the support structure and the flexible cover through the body inner lumen and positioning the flexible cover distal to an expandable member of the catheter, the expandable member defining an expandable member inner lumen in fluid communication with the body inner lumen, and wherein the expandable member is located at the distal body portion of the catheter; 
 while the support structure is positioned within and extends through the body inner lumen and the expandable member lumen, positioning the flexible cover over the expandable member; 
 distally introducing the catheter and the delivery-assist tool into a delivery sheath, wherein the flexible cover is configured to facilitate compression and retention of the expandable member into a delivery configuration while the catheter is being advanced through the delivery sheath and while the support structure extends through the body inner lumen and the expandable member inner lumen; and 
 applying a proximal force to the support structure to invert the flexible cover and proximally withdraw the flexible cover into the body inner lumen of the catheter, enabling the expandable member to expand radially outward from the delivery configuration to a deployed configuration. 
 
     
     
       20. The method of  claim 19 , wherein the flexible cover has a funnel shape defining a proximal-facing mouth when the flexible cover is disposed over the expandable member. 
     
     
       21. The method of  claim 19 , wherein the flexible cover is configured to neck down the expandable member by at least applying an axial tensile force to the expandable member while the flexible cover is disposed over the expandable member and while the flexible cover and the expandable member are disposed within the delivery sheath. 
     
     
       22. The method of  claim 19 , wherein the flexible cover comprises a braided mesh. 
     
     
       23. The method of  claim 22 , wherein the braided mesh defines a first braid angle that is greater than a second braid angle of the expandable member. 
     
     
       24. The method of  claim 19 , wherein the flexible cover comprises a plurality of polymer flaps extending proximally and radially outward from the support structure. 
     
     
       25. The method of  claim 19 , wherein the support structure defines a varying hardness along an axial length of the support structure.